Carburetor arrangement



March 1946. A. B. METSGER CARBURETOR ARRANGEMENT Filed July 1 1943 2 Sheets-Sheet l r rlliilinilnrrAnl INVENTOR flmezo .5. M57565 v if,

ATTORNEY March 12, 1946. METSGER CARBURETOR ARRANGEMENT Filed July 1, 1943 2 Sheets-Sheet 2 ATTORNEY surrounding gas pressure,

Patented Mar. 12, 1946 UNITED STATES PATENT OFFICE.

2,396,279 CARBURETOR ARRANGEMENT I Alfred B. Metsger, United States Navy Application July 1, 1943, Serial No. 493,139

1 Claim. (01. 48-184) (Granted under the act of March 3, 1883, as amended April 30, 1928; 370 0. G. 757) The present invention is intended to permit variation of airflow through a carburetor for a given metering suction, for density and compressibility compensation, and for other purposes.

In accomplishing the above purposes in the present device the following means and/orieatures are combined to form the complete carburetor arrangement of the present invention.

Some of thesemeans just mentioned comprise a series of devices to accomplish the result as follows:

In order to permit Venturi area control with low control forces, a servo operated Venturi plate is used;

For giving a mechanical indication of the density of a gas, especially air,-a device called a'density calculator is used;

A means which gives a mechanical indication of the ratio of two gas pressures is used in this present invention, and same is designated a pressure ratio calculator;

For producing an angul 'r motion equal to that of an angular input, but w much greater torque; and deriving operating power from suction and a suction servo torque multiplier is used;

In order to automatically connect an air or gas suction line with the greater of two sources of suction, a suction selector valve is used; and

A device is provided herein which is used for controlling the amount of fuel admitted to the carburetorwhich is dependent upon the pressures found in the throat and other parts of the air or gas inlet. I

The above features and devices are combined in the present carburetor arrangement to produce a device of singular utility, the'features of which will be more fully explained as the description proceeds herein.

In the drawings forming a part of the present specification:

Fig. 1 is a diagrammatic cross-sectional elevation of the present invention showing substantially all the above named parts of same.

Fig. 2 is a longitudinal detail section taken on line 2-4 of Fig. 1, of a controlled vent and cap used in connection with the Venturi plate of the invention.

Fig. 3 is a vertical cross-section on line 3-3 of Fig. 5, which last is a "suction torque multiplier" forming part of this invention.

Fig. 4 is a vertical section on line 4-4 of Fig. 5.

Fig. 5 is a. vertical longitudinal section through the above mentioned suction servo torque multiplier, used with this invention.

The variable area Venturi meter which numeral I indicates the body of an air carburetor inlet passage to an engine. The numeral 2 represents a Venturi spoon which is pivo'tally mounted on a pintle 3 and is in the nature of a fiat metal plate, having an inclined portion 4 and a curved portion '5 thereon; and which slidably engages in a recess or pocket 6 formed in the body portion of the air inlet casing' I as clearly shown in Fig. l of the drawings.

It will be noted that leakage of air is provided against by means ofsealing or packing strips 8 on the end 9 of the Venturi spoon 2 where it engages against the upper face of the recess 6 mentioned. The form of the air inlet casing I is shaped at III, N, and II, to accommodate the various parts necessary in the construction of the device.

The casing I has mounted thereon a closed container l3 shaped as shown in Fig. 1 for the pur- Venturi shape as shown and forms one side of a Venturi passage or preferably rectangular crosssection, and as above'stated is pivoted and'movable about the pintle 3 so that when the said plate is moved back and forth by means of the servo finger H," the throat portion l5 of the air inlet I6, can be enlarged or diminished automatically ormanually as will be described below.

Numeral N indicates a static throat pressure take-off located in the region of minimum crosssectional area of the Venturi meter. Impact tube I8 is arranged to obtain the total inlet pressure in the passage l6 and is used for accurate determination of the air pressure admitted to the carburetor at l6 as will be fully described herein. A

fixed vent 20 in the wall of the Venturi spoon is positioned in the expanding section of the venturi, at such a point that the efiective force or pressure behind the spoon 2 will overcome by a slight margin the effective force on the workin face 01 said spoon.

Numeral, 2| indicates a controlled vent which appears in enlarged detail in Fig. 2 of the drawings and is positioned in the wall of the Venturi spoon! and has a proper size and location relative to the fixed vent 20 so that it overcomes the effect of the latter and causes motion of the spoon resulting in an increase or Venturi size at the throat l5 thereoiwhen the vent 2| is partially or pose of housing various parts of the invention, described herein.- The Venturi spoon has a with a connecting rod 3!.

tioned on the servo finger l4 near the control vent 21 as shown ,in Fig. 2 detail for the purpose of varying the effective area of the control vent 2! by varying the amount of closure of the orifices 24.

In the enlarged detail of the parts 2|, 22, and H shown in Fig. 2 of the drawings it will be seen that the cylindrically shaped part 22, which is fastened to the finger l4 moves axially with respect to part 2| varying the eifective' area of openings 24, 24 for the purpose of varying the pressure drop through these openings.

It will be noted that the servo finger. I4 is preferably pivoted on the same axis 3 as the Venturi spoon 2 and may be controlled manually or automatically with a reciprcatory movement through the seal H formed in the wall 25 of the casing l. The seal l I reduces leakage through the said wall 25 around the servo finger Id, The numeral 28 indicates a fixed cam support preferably mounted on the bottom wall 21 of the closed container l3. At point 28 on the support 26 is pivotally mounted a cam 29 which is pivotally connected at 39 The cam 29 has an arced slot 3 la therein in which the arm extension 32 of the servofinger i4 engages by means of the pintle 33. It is evident that the servo finger It and the control vent 2i can be operated by means of the connecting rod 3!, and the actuation of 3| by means of the apparatus shown in in closed container 83 will be fully described e ow.

2,896,279 completely open. A vent control cap 22 is posias shown. A' slide 38 is adapted to reciprocate in the slot 36 of the ratio arm. A temperature indi- .cator 39 which in this case is a bimetal coil positions the slide 38 a distance from the pivot point 31 proportional to the inlet temperature obtained by the inlet 40 from the air inlet 16 as shown. The pressure bellows ll has an operatingrod li which connects it pivotally with the slide 38 in the ratio arm 35 as shown.

The bellows M as it reciprocates according to air pressure gives motion to the rod 42 as is at once seen, and to theratio arm 35 proportional to the inlet pressure through part 49, in a line of about 90 with the direction of ratio arm 35, The pressure bellows 4|, it will be seen, is pivotally mounted at 43 in the support 44 carried on the inner face of the wall 1.

The angular position of the ratio arm 35, it will be noted, varies approximately directly as the inlet air pressure around the bellows 4|, and inversely as the corresponding temperature; e. g., it varies as the density of the gas or air surrounding the calculator, It is seen that the ratio arm 35, then is mechanically operated according In connection with the variable area Venturi meter" just described, air to be metered to the engine enters the carburetor by passage 3t and through the air inlet 06, and is metered as usual in a venturi, except that the area of this venturi may be varied manually or automaticallyas described herein. The pressure on the outer side of the Venturi spoon 2 is varied along the direction of airflow or downward as shown in Fig. 1 of the drawings. The fixed. vent 29 is placed at a point in the passage as where the fluid pressure has recovered to an intermediate pressure value.

{ Leakage by the sides or edges of the spoon 2 is kept at a small value by reasonably small clearances, with the walls of the duct or passage 33.

It is noted the fixed vent is alone would lead to a net force or pressure behind the Venturi spoon 2 tending to reduce the Venturi cross-sectional area. Control vent 29 if fully open overpowers the effect of the fixed vent 20 causing the Venturi area to increase in the area of the throat portion i5 of the passage 34. The Venturi spoon would move to theright in Fig. 1 untilthe vent control cap 22 closes the vent 2! to such an extent that the Venturi spoon is in equilibrium, The Venturi plate 2a then, follows the motion of the vent control cap 22 which last is controlled by the servo finger 14, the latter being operated manually or automatically as desired.

The above completes the description of the variable area venturi and the operation of the Venturi plate 2a used in connection therewith.

The "density calculatof One of the means used in operating the con .necting rod 3i above mentioned comprises what is called a density calculator which is used to give a; mechanical indication of the densit of to the pressure and temperature of the gas or air whose density is being measured. The angular motion of the ratio arm 35 may be used to position a cam 45 and drive an output connecting rod 46 by means of the cam follower 41, and to efi'ect the operation of the connecting rod 3| by means of the cross rod 48. It is noted that the pintle 31 is a fixed axis supported within the container l3 but revolvably mounted therein, and the connecting rod 46 slidably operates through a fixed support 49. y

The cam follower d1 follows the edge 59 of the cam 45 and is revolvably mounted at El in the end of the connecting rod 45. The cross rod 68 is slidably and pivotally mounted in the fixed support 52 by means of sliding block H, and pivotally connected at 53 to the connecting rod 3i as shown. The ends of the cross rod 48 at 55 and 55 are forked to slidably receive the pintles 56 and 5'lwhich are on the ends of .the connecting the fluid used in the present device especially the air portion thereof. A ratio arm 35 having a slot 36 therein is mounted on a revolvable but fixed pivot or pintle 3'! within the closed container 12 rods 35 and 58 respectively.

From the above it is seen that the pressure of the air admitted to the chamber of container it through inlet 49 and the temperature thereof operates the "density calculator" 59. The calculator has a mechanical operating efiect on the connecting-rod. 3i, and servo finger H and therethrough the movement of the Venturi spoon 2 is conformably operated at the throat l5 of the Venturi meterin accordance with the pressure and temperature of the inlet air from inlet lt. From the above it is seen that the "density calculator" gives a mechanical indication of the density'of a gas or of air and can be mechanically used as one of the features or factors in the operation of the Venturi spoon 2 and the venturi.

The "pressure ratio cal culatof The pressure ratio calculator which is used to give a mechanical indication and effect of the ratio of two gas or air pressures may be described W I asoeme ably therein. n will be noted that static gas pressure in the throat I! of the venturi is taken at points l1 and through the pipe 81 and delivered to the pressure bellows 82 at 88. The pressure bellows 82 is carried pivotally at 89 in the fixed support 18, which is mounted on the inner face of the wall of the closed container l3. It will be at once seen that as the pressure bellows 82 expands or contracts due to the pressure through pipe 61, and aiiects the operating rod 1| which is pivotally mounted at 12 on the slide 66 that the ratio arm 63 will be angularly operated about the pivot point 84.

The pressure bellows BI is actuated by the gas or air which is within the closed container 18" and comprises the following parts. The "pres sure bellows BI is enclosed in the cage 18, and moves the cage 13, which is slidably mounted at 18, .18 on. the fixed slide, represented by rods 18, 15. The wire 11 delivers the response of the pressure bellows 6| to, the slide 68 by means of the pulley 18 which is mounted on the fixed revolv- Figs. 3 and clear y. and said vents are controlled by the input lever, depending on the angular position of said lever 88 on the valve section 81 as -is at once understood. In the operating chambers 88, 88 is located the moving division wall 8| which is preferably made integral with the body of the valve section 81. Centrally of'the operating chambers is positioned a fixed shaft 82 (which may be shafts 81 or 64 if so arranged),

able pintle 18 carried in the closed container 18. I

It is noted that the portion 88 of the guide wire 11 is in line with the direction slot of the ratio arm 83, and the spring 8| keeps the slack out,

of the wire "when the pull in said wire 11 is pivotally mounted at 84 in the end of the con- 1 necting rod 58 before mentioned. The said rod 88 slidably operates in the fixed support 88 and by means of the pintle 81 said rod actuates the cross rod 48 and in turn the connecting rod 8| of the Venturi control device by means of the cam 28 and its associated parts.

It will be noted that the angle of rotation of the ratio arm 88 varies approximately directly as having a hollow center duct 83 therethrough. A fixed .division wall 84 is part of or rigidly mounted on the central-shaft 82.

Restricted vents 88, 85 in the central fixed shaft 82 provide communication from the operatlng, chambers 88, 88 to the center or suction duct 83, a

It is seen that when the input lever 88 is given an angular or arcial displacement one of the vents 88 is opened partially or fully to one of the proximate corresponding slots 88. This vents one of the operating chambers 88, 88 to the gas pressure surrounding the device itself, throughone of, each 'of the inlet ducts 88, ducts 88, and 88 shown in Fig. 5 clearly.

It will be noted that the fixed division wall 84 is integral with and part of the fixed shaft 82 and when gas pressure is admitted to either.

with reference to the exterior periphery of .the'

fixed shaft 82, and the-interior wall of the valve section body 81:: respectivelyfto reduce gas leak-- age thereabout. Until the input lever or arm 88 is given an angular displacement, and while both ducts 88, :88 are in closed positions, both of the .operating chambers 88, 88 are at the suction pressure delivered by the suction pipe I88, Fig. 5, by means oi the suction duct 88 and the restricted ports 88, 88 of the central shaft 82. However,

the output of the bellows 62 and inversely as theoutput of the bellows 8i;e. g., as the ratio of the two pressure bellows outputs. The angular motion of the ratio arm, ofcourse, may be used to position a cam, such as 82 to drive an outputv "connection rod 88 and control the parts of a servo finger apparatus, or for other purposes,

' such as actuating-a "suction torque multiplier described below.

H Suction torque multiplier The auction torque multiplier l2! just men tioned is intended to produce an angular motion equal to that of an angular input but with much greater torquederiving its operating power from auction gas pressure and from gas pressuresurrounding the multiplier device. The device in hand comprises the following parts and is clearly grees, but it less circular travel is required then i said degree of revolution o1v the body 81a of the valve section 81 may be cut down to a sector of a cylinder instead 01'- a complete cylinder.

Each'of the valve section vents 88, 88 in section 81 are ducted or lead to one or the sub-operating chambers 88, 88 of the multiplier shownin when the much larger controlled vents 88, 88 are opened by means or the actuation of the input lever 88, the gas pressure which surrounds the whole torque multiplier prevails over the pressure admitted by the suction pipe I88 and a pressure inequality is set up between the two chambers 88. The'diil'erence in pressure in the chambers 88. 88 tends to act on the division walls 8| and 84 and moves the body 81:; of the valve section 81, an amount corresp nding to the circular motion of the input arm 88.

' After this movement of plished, it is seen that the input arm 88 and the body of the valve section 81' resume their equilibrium position through the equalization of the pressure in the chambers 88, 88 so that little or no more external gas is admitted to the chambers88 through either of the ducts 88 and motion of the various parts of the device ceases. The motion of the cam 81 then, acts in accorda cam 81 and a cam follower such as 41, or'-88 Fig. 1, or to, drive an output arm or lever.

It will be noted in the above description two kinds of means are used to operate the cam fol-- lowers 41 and 83, andconnecting rods 48 and 88.' In'the first instance shown in Fig; 1 of the drawings where no suction torque multipliers l2| (Fig. 5) are used, iii-transmitting motion from the cam is accoxn' ratio arms 35 and 63 to the cam followers 41 and 83 respectively, it is seen, said arms 35 and 63 are required to be rigidly mounted on said shafts 31 and 64; likewise cams 50 and 82 are required to be rigidly mounted on said respective shafts. Shafts 31 and 64 are themselves revolvably mounted in their supports (not shown) so that when ratio arms 35 and 63 are angularly moved, said cams are correspondingly operated in order to actuate the cam followers 41 and 83, and rods 46 and 58. The selector valve I20 'parts H4, H5, and pipes H and III in this case are eliminated as they are used only when the torque multipliers I 2I are used. I

In the second case where suction toque multipliers such as I2I (Figs. 3, 4.- and are used, conditions are somewhat reversed. The shafts 31 and 64 which correspond to the shaft 92 of Figs. 3, 4 and 5 are then not made revolvable, and the ratio arms 35 and 63 of Fig. l, (which correspond to input lever 86, Fig. 3), are made revolvable with reference to shafts 31 and 64, as is at once understood from the description of "suction torque multiplier, I2I as explained above. The cams 50 and 82 are'also made revolvable with reference to the shafts 31 and 64 when the torque multiplier is used in connection with the device shown in Fig. 1 of the drawings. a It will be noted in the first instance above mentioned that where no torque multipliers are used, the operation of the Venturi spoon is not influenced by the gas pressure taken from the inlet passage 34 at point H9 through pipe III, nor by the pressure through pipe IIO. However, the pressure taken at point I1 at substantially the same point as I I8 in the throat I5 of passage- 34 has a bearing on the operation of cam 82, and on the Venturi spoon 2 due to the use of the pipe 51 used to operate bellows 62, and arm 63 before described.

The suction selector value I according to the position of the spindle.

The grooves I08a, I08a insure the proper venting of the space I01 between the spindle ends and the ends of the recesses I05, I06, when the valve is in a closed position on either side of the valve seat I02 or I 03.

The inlet ports I08, I00 are connected with pipes IIO, III respectively, and suction port, I I2 connects with the dualended pipe II3 which forms two branches I I4, I I5 leading to the torque multiplier IZI above described. The valve heads or discs II 6, H1 are arranged to be in contact with either one of the valve seats I03 or I02, but with only one at a time.

The net force or pressure on the valve discs II6,'II1 moves either one of them and spindle I04 within the valve, toward the side of lower gas pressure as received from pipes H0 or' III, seating the valve between the source of higher It is evident that as the pipe II 0 connects with the .Venturi suction port H8 at the throat I5 of the venturi, and pipe III connects with the blower inlet suction port H0 in the passage 34 at a point after the gas pressure in the inlet passage 34 has passed the Venturi spoon 2, that the gas furnished by the suction selector valve I20,

to the pipe II3 will have a pressure equal to the lower pressure of gas or air withdrawn through the ports H8, H9 in the carburetor inlet passage 34, whichever point in the passage 34 fur- The, carburetor assembly The various elements and devices described above are assembled to form a simplified carburetor in Fig. 1 of the drawings. The Venturi spoon 2 is positioned by the servo finger I4 as before described either manually or automatically, said finger being mechanically positioned by the cam 29. The input to this cam 20 as shown and above described is a function of the sum of the logarithms of the density and pressure ratio corrections above described in connection with the devices shown in and about the closed which controls the cam 29, and hence the servo finger I4 and the Venturi spoon 2 as is readily understood.

It will be noted that while the arrangements have been made for the cams 50 and 82 of Fig. 1 and the cam 01 of the suction torque multiplier Fig. 3 to push downward the connection rods 46 and 58 and the connecting rod 3| by means of the cross arm 48, it is evident that means must be used to push upward the rod 3| as soon as the cams above mentioned permit such action to be taken. This is provided for by means of a coil spring 23 which is mounted on the pintle 28 which is carried by the fixed cam support 26. The said spring 23 bears against the outstanding arm I4I of the cam 20 at point I42 and pushes the connecting rod 3| upwards when permitted so to do by the cams above mentioned.

This carburetor arrangement automatically controls the size of the throat I5 leading to the inlet passage 34 and places the Venturi spoon 2 automat cally in position according to the combined operation of the various devices such as 59, 60, 3|, I4 as above described. Said devices within the container I3 are, of course, also affected by means of the suction selector valve I20 as before explained. Suction pressure to drive the torque multipliers I2I is taken selectively from the venturi suction port H8 or the blower inlet suction port II 0 whichever gives the lesser suction pressure.

The selector valve I20, of course, selects the proper source of suction from the ports H8, or II9 fed to the torque multipliers I2I, I2I on the shafgs 31 and '64, (Fig. 1), or hollow shaft 02 of Fig.

The metering pressures PI and P2, taken through parts I8 and I1 respectively, are delivered across the air diaphragm I22 in the "pressure responsive'device" I23. The diaphragm I22 which is preferably of stiff material is provided latter is provided with the fuel charging orifice I9.

A second "pressure responsive device I30 surrounds the valve stem I26 between the charging box I28 and the device I23. Said device I30 is provided with a stiff diaphragm I3I which is at tached by flexible material at I32, I32 where it is attached to the walls I33 and I34 of the device no. Said diaphragm m is also rigidly attached at I35 to the valve stem I28, and it is seen that the two diaphragms I22 and I3I co -act upon the valve stem I26 and the valve I21. 3

The metering pressure across the fuel-orifice I38 is also across the fuel diaphragm I 3!, the total forces on the twodiaphragms I22 and I3I are automatically balanced by the action of the fuel regulating valve I31 aslong as fuel is supplied to the fuel inlet orifice I! under suflicient pressure. Fuel is delivered to the carburetor pas sage 34 through the delivery pipe I 38. A butterfly valve I" my be inserted in the inlet passage ,34 if desired (or the purpose of controlling the flow of air passing to the engine.

I From the above description of the various parts of the present carburetor arrangement it is seen ufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

I claim: a

In a means for regulating the pressure and amount of supplyof gaseous fuel through a carburetor inlet supply pipe which is provided with a venturi therein in accordance with a combination of factors created in the inlet pipe, such as the density of the air at the entrance of the inlet passage, the air pressures found at the throat of the venturi, as modified by the air pressure at I the entrance of the inlet passage, and the pressure of air and gas found in the inlet passage at a point beyond and below. the discharge from the venturi, comprising a closed pressure responsive device, a flexibly mounted air pressure actuated diaphragm therein, dividing said device into two operating chambers, means for admitting air pressure to the upper chamber from the entrance of the inlet passage, means for admitting fluid pressure to the lower chamber of said device that a fuel and air mixture is supplied to the engine through the orifice II! from the passage 34, which is regulated in proportions bya series of factors and devices shown and described in the above specification, and which appear in the Figs.

1 to 5 of the drawings. practically all of which The invention described herein may be manfrom the throat of the venturi, a ertically disposed valve stem and head attached to the aforesaid diaphragm, a second closed pressure responsive device, a flexibly mounted fuel pressure actuated diaphragm in the last-named pressure device, rigidly attached to the valve stem, a fuel charging box mounted beneath the second pressure responsive device, having a fuel charging orifice' and a valve seat therein, and communicating with the lowerportion of the chamber of the second-named pressure responsive device, and means for admitting fuel under pressure from the charging box to the inlet passage at a point below the venturi and also admittingsimilar pressure to the upper portion of the chamber of the second-named pressure responsive device, the above arrangement of parts being intended to open and close the fuel charging valve upon the joint action of the diaphragms in the two presand fuel, found in the various parts of the inlet passage, as desired.

. ALFRED B. METSGER. 

